The biggest activity during this period was the relocation from Japan in April 2018. We opened a research laboratory in Bethesda campus and started pilot experiments for the study of thymus biology. We also opened mouse colony in Frederick campus. Frozen embryos of genetically modified mice have been transported from Japan and redelivered in Frederick. We started the recruitment of laboratory members and have hosted an undergraduate student under the Summer Internship Program. Meanwhile, we revealed that thymi of postnatal mice contain approximately 9 x 10*5 beta5t+ cortical thymus epithelial cells (TECs) and approximately 1.1 x 10*6 Aire+ medullary TECs, numbers 10 to nearly 100-fold larger than previously estimated using conventional enzymatic digestion, suggesting that the use of conventional enzymatic digestion methods for the isolation of TECs has resulted in the underestimation of the cellularity, and possibly the biology, of TECs.